Gossip Girl, singular

It drives me crazy when I read references to "Gossip Girls", plural, in connection with the TV show or series of books. It's a Gossip Girl, singular, to whom all gossip is sent. No one knows who the person is. Person. Singular. Sorry to be a grouch, but when even Michael Cart gets it wrong, it's time to start the revolution.
OK. Maybe "revolution" is going too far.